Consumers are becoming more concerned with the quality of their drinking water. When RO is used in a residential setting, a user desires to have clean water on demand. However, typical RO systems for home use have slow purified water output. Thus, typical RO systems utilize a holding tank to store water.
For example, in a typical system, water is pulled from the water line. This water is run through a carbon prefilter (often a sediment prefilter is included as well). The water then runs through a reverse osmosis membrane element. The concentrate stream from the membrane element flows to the drain, while the permeate water runs into a storage tank—usually with 1-2 gallon storage capacity. From the storage tank the permeate water runs through a second carbon filter (a polishing filter), then to a separate faucet usually mounted on the kitchen sink. Because these systems are only capable of producing a small rate of permeate, the storage tank is required on almost every system. Moreover, there are several component costs to these systems that limit the bottom line manufacturing cost of these units, with the membrane element and storage tank representing the largest overall percentage.
Accordingly, what is needed is a low-cost, compact, full-featured, pumpless, and tankless RO system for residential use.